1. Field of the Invention
This disclosure relates to an image formation apparatus, for example, a color electrophotographic printer (hereinafter also referred to as a color printer), and one suitably applicable to toner for use in printing with the color printer.
2. Description of Related Art
The conventional color printer, for example, forms toner images of clear, yellow, magenta, cyan, and black in five print engines, sequentially transfers the toner images one on top of another to the surface of an intermediate transfer belt, and then transfers these five color toner images from the surface of the intermediate transfer belt to the surface of a sheet. The color printer then fixes these five color toner images to the surface of the sheet through heating and pressing to form a color print image.
In the conventional color printer, black toner contains carbon, which is easily charged with a polarity opposite to that of the other color toners. For this reason, for some of the linear parts of a black toner image to be covered with a clear toner image, the conventional color printer forms a combination of the other yellow, magenta, and cyan toner images, instead of the black toner image.
In this way, in transferring the black toner image and the other color toner images, one on top of another, to the surface of the intermediate transfer belt or the surface of the sheet, the conventional color printer makes the black toner less likely to be spread around the transfer position due to the repulsion of the black toner away from the other color toners which may cause color blurring in the print image (for example, see Japanese Patent Application Publication No. 2012-42882, pp. 6 to 8 and FIG. 7).